diff --git a/ext/libpng/gstpngenc.c b/ext/libpng/gstpngenc.c
index 7da1fafe77..d3ebc49c95 100644
--- a/ext/libpng/gstpngenc.c
+++ b/ext/libpng/gstpngenc.c
@@ -324,6 +324,7 @@ gst_pngenc_handle_frame (GstVideoEncoder * encoder, GstVideoCodecFrame * frame)
   png_write_end (pngenc->png_struct_ptr, NULL);
 
   g_free (row_pointers);
+  gst_video_frame_unmap (&vframe);
 
   png_destroy_info_struct (pngenc->png_struct_ptr, &pngenc->png_info_ptr);
   png_destroy_write_struct (&pngenc->png_struct_ptr, (png_infopp) NULL);